Nail grinding pen and nail grinding host machine

ABSTRACT

The present invention discloses a nail grinding pen, which comprises a pen barrel, a motor, and an inner body. The inner side of the pen barrel has a receiving space, and an opening connected to the receiving space provided on one side of the pen barrel. The motor is arranged in the receiving space, and driven by electric power to rotate the rotating shaft. The inner body is connected to the rotating shaft, and one end of the inner body facing the opening has a gripper for fixing a grinding head, so that the motor is able to drive the grinding head into rotation by rotating the gripper.

BACKGROUND OF THE INVENTION 1. Technical Field

The present invention relates to a nail grinding pen and a nail grindinghost machine. More particularly, the invention relates to a nailgrinding pen and a nail grinding host machine for the beauty treatmentof fingernails.

2. Description of Related Art

Hand gestures are frequently used in interpersonal communications tohelp accentuate the ideas being communicated. This explains why aperson's hands are often the focus of attention in addition to theperson's face, and why a woman's hands are also referred to as hersecond face. With the development of technology, the market has beensupplied with a great variety of nail beautifying devices such thatmeticulously beautified nails have gradually become a manifestation ofmodern women's fashion and an important feature of a woman's overallappearance.

During a nail beautifying process, nail files or emery boards aretypically used to wear down the residues of gel nails or dip powdernails after such artificial nails are removed, or to shape acrylic nailsby trimming the edges of or shortening such artificial nails. Theconventional nail files or emery boards, however, are subject tolimitations imposed by their shapes and sizes and therefore have problemdoing their work in relatively small areas. Furthermore, the relativelylarge movements of nail filing tend to cause dispersion of the resultingnail filings, or nail dust, which ends up suspended in the air and islikely to harm an inhaler's health.

BRIEF SUMMARY OF THE INVENTION

Compared with its prior art counterparts, the nail grinding pen of thepresent invention is more versatile in use, is effectively enhanced inits nail grinding effect and operability, and can reduce the dispersionof nail dust in the air.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of a nail grinding pen according to thepresent invention;

FIG. 2 is an exploded view of the structure of the nail grinding pen inFIG. 1 ;

FIG. 3 is another exploded view of the structure of the nail grindingpen in FIG. 1 ;

FIG. 4A shows how the gripper of a nail grinding pen according to theinvention is opened by operating a push switch;

FIG. 4B shows how the gripper in FIG. 4A is closed by operating the pushswitch;

FIG. 5A shows how the gripper of a nail grinding pen according to theinvention is opened by operating a rotary switch;

FIG. 5B shows how the gripper in FIG. 5A is closed by operating therotary switch;

FIG. 6 is a sectional view of the nail grinding pen in FIG. 1 to FIG. 3;

FIG. 7A shows one of the various rotating shaft designs for the motor inthe invention;

FIG. 7B shows one of the various rotating shaft designs for the motor inthe invention;

FIG. 7C shows one of the various rotating shaft designs for the motor inthe invention;

FIG. 7D shows one of the various rotating shaft designs for the motor inthe invention;

FIG. 7E shows one of the various rotating shaft designs for the motor inthe invention;

FIG. 7F shows one of the various rotating shaft designs for the motor inthe invention;

FIG. 8 is a partial sectional view of the nail grinding pen in FIG. 1 toFIG. 3 ;

FIG. 9 is another partial sectional view of the nail grinding pen inFIG. 1 to FIG. 3 ;

FIG. 10 is still another partial sectional view of the nail grinding penin FIG. 1 to FIG. 3 ;

FIG. 11A shows how the rolling ball in the invention moves when therotating ring is rotated;

FIG. 11B shows how the rolling ball in the invention moves when therotating ring is rotated;

FIG. 11C shows how the constricting unit in the invention works when therolling ball moves from the first end toward the second end;

FIG. 11D shows how the rolling ball in the invention moves when therotating ring is rotated;

FIG. 11E shows how the rolling ball in the invention moves when therotating ring is rotated;

FIG. 11F shows how the constricting unit in the invention works when therolling ball moves from the second end toward the first end;

FIG. 12A shows one of the various electrical connection port designs forthe motor in the invention;

FIG. 12B shows one of the various electrical connection port designs forthe motor in the invention;

FIG. 12C shows one of the various electrical connection port designs forthe motor in the invention;

FIG. 13A is a partial sectional view of one of the nail grinding pensaccording to the invention;

FIG. 13B is a partial sectional view of one of the nail grinding pensaccording to the invention;

FIG. 14 is a partial sectional view of another nail grinding penaccording to the invention;

FIG. 15 is another partial sectional view of the nail grinding pen inFIG. 1 to FIG. 3 ;

FIG. 16 is still another partial sectional view of the nail grinding penin FIG. 1 to FIG. 3 ;

FIG. 17A shows one of the nail grinding pens according to the inventionincorporating a fan;

FIG. 17B shows one of the nail grinding pens according to the inventionincorporating a fan;

FIG. 18 is a partial perspective view of a nail grinding pen accordingto the invention;

FIG. 19A shows one of the nail grinding pens according to the inventionincorporating an auxiliary light;

FIG. 19B shows one of the nail grinding pens according to the inventionincorporating an auxiliary light;

FIG. 20 shows the exterior of a nail grinding host machine according tothe invention;

FIG. 21 shows the devices in the nail grinding host machine in FIG. 20 ;

FIG. 22 is a block diagram of the nail grinding host machine in FIG. 20and FIG. 21 ;

FIG. 23A-23E are block diagrams of some alternative nail grinding hostmachines according to the invention;

FIG. 24A is a block diagram of some more alternative nail grinding hostmachines according to the invention;

FIG. 24B is a block diagram of some more alternative nail grinding hostmachines according to the invention;

FIG. 24C is a block diagram of some more alternative nail grinding hostmachines according to the invention;

FIG. 25A shows a receiving mechanism of different nail grinding hostmachines according to the invention;

FIG. 25B shows a receiving mechanism of different nail grinding hostmachines according to the invention;

FIG. 25C shows a receiving mechanism of different nail grinding hostmachines according to the invention;

FIG. 25D shows a receiving mechanism of different nail grinding hostmachines according to the invention;

FIG. 25E shows a receiving mechanism of different nail grinding hostmachines according to the invention;

FIG. 26 is a block diagram of another nail grinding host machineaccording to the invention;

FIG. 27 shows an angle between a nail grinding pen according to theinvention and a horizontal plane; and

FIG. 28 is a block diagram of yet another nail grinding host machineaccording to the invention.

DETAILED DESCRIPTION OF THE INVENTION

As is conventionally done, the features and elements shown in theaccompanying drawings are not drawn to scale but are drawn to bestillustrate specific features and elements that are related to thepresent invention. In addition, identical or similar reference numeralsare used throughout the drawings to indicate similar elements or parts.

The embodiments described below are not intended to impose excessivelimitations on the present invention. A person of ordinary skill in theart may modify or change the embodiments discussed herein withoutdeparting from the spirit or scope of the invention, and all suchmodifications and changes shall be viewed as falling within the scope ofthe invention.

As used herein, terms such as “comprise,” “include,” “have,” and“contain” are inclusive or open-ended unless otherwise stated andtherefore do not exclude elements or steps that are not specified. Theterms “a” and “said” may be construed as referring to a single referentor plural referents. The term “one or a plurality of” means “at leastone” and therefore may be used to identify a single feature or amixture/combination of features. Moreover, unless otherwise stated, theterm “provided on an article” as used in this specification and theappended claims may be construed as being directly or indirectlyattached to a surface of the article or as contacting the surface of thearticle in other ways, wherein the definition of the surface should bedetermined according to the context and common knowledge in the art.

Each “equipment,” “device,” “apparatus,” or “module” used in the presentinvention, or its function, may be implemented by a single chip or by aplurality of chips that work together; the invention has no limitationon the number of such chips. The aforesaid chips may be, but are notlimited to, processors, central processing units (CPUs),microprocessors, digital signal processors (DSPs), application-specificintegrated circuits (ASICs), programmable logic devices (PLDs), or acombination of the above; the invention has no limitation in thisregard.

One embodiment of the present invention is described below withreference to FIG. 1 , FIG. 2 , and FIG. 3 , which are a perspective viewof a nail grinding pen according to the invention and two exploded viewsof the structure of the nail grinding pen. This embodiment discloses anail grinding pen 100 that includes a nail grinding pen barrel 10, amotor 20, and an inner body 30. The nail grinding pen barrel 10 has areceiving space SP therein. One end of the nail grinding pen barrel 10has an opening OP in communication with the receiving space SP. Themotor 20 is provided in the receiving space SP and has a rotating shaft21 to be driven to rotate by electricity. The inner body 30 is connectedto the rotating shaft 21 of the motor 20. The rotating shaft 21protrudes from the motor housing 22 by a length less than 15 mm, such asbut not limited to 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm,10 mm, 11 mm, 12 mm, 13 mm, 14 mm; the invention has no limitation inthis regard. The end of the inner body 30 that faces the opening OP isprovided with a gripper 31. The gripper 31 is configured to secure agrinding head GH so that by rotating the gripper 31, the motor 20 candrive the grinding head GH into rotation.

The gripper 31 can be opened and closed by operating each of thefollowing two types of switches. Please refer to FIG. 4A and FIG. 4B,which show how the gripper of a nail grinding pen according to thepresent invention is opened and closed by operating a push switch. Inthe embodiment shown in the drawings, the nail grinding pen barrel 10 isprovided with a push switch 11A coupled to the gripper 31. The pushswitch 11A can be pushed forward and pulled rearward to switch thegripper 31 between an opened state and a closed state. In FIG. 4A forexample, the push switch 11A is pushed forward (or leftward as shown inthe drawing) and thereby moved slightly forward such that the gripper 31is expanded by an internal linkage mechanism and thus releases thegrinding head GH. In FIG. 4B, the push switch 11A is pulled rearward (orrightward as shown in the drawing) and thereby moved back to itsposition in FIG. 4A such that the gripper 31 is radially constricted bythe internal linkage mechanism and thus grips the grinding head GH. Thelinkage mechanism of the push switch 11A can be implemented in many waysand can be any suitable mechanism, and the techniques by which toimplement the linkage mechanism of the push switch 11A are conventional.As the design of the linkage mechanism of the push switch 11A is not afeature for which patent protection is sought by the applicant, theworking principle of the linkage mechanism will not be detailed herein.

Another embodiment of the switch for opening and closing the gripper 31is illustrated in FIG. 5A and FIG. 5B, which show how the gripper of anail grinding pen according to the present invention is opened andclosed by operating a rotary switch. In the embodiment shown in thedrawings, the nail grinding pen barrel 10 is provided with a rotaryswitch 11B coupled to the gripper 31. The rotary switch 11B can berotated to switch the gripper 31 between an opened state and a closedstate. In FIG. 5A for example, the rotary switch 11B is rotatedclockwise (as indicated by the arrow A1 in the drawing) such that thegripper 31 is expanded by an internal linkage mechanism and thusreleases the grinding head GH. In FIG. 5B, the rotary switch 11B isrotated counterclockwise (as indicated by the arrow A2 in the drawing)such that the gripper 31 is radially constricted by the internal linkagemechanism and thus grips the grinding head GH.

Please refer to FIG. 6 for a sectional view of the nail grinding pen inFIG. 1 to FIG. 3 . As shown in FIG. 6 , the inner body 30 in thisembodiment essentially includes a pushing post 32; the gripper 31, whichis provided at the front end of the pushing post 32; a position-limitingbarrel 33 surrounding the gripper 31; and a shaft sleeve 34 provided atthe rear end of the pushing post 32 and attached to the rotating shaft21 so that the motor 20 can drive the pushing post 32, the gripper 31,and the position-limiting barrel 33 into rotation. In one embodiment,the shaft sleeve 34 is made of plastic or metal. In a preferredembodiment, the material of the shaft sleeve 34 is plastic to enhanceself-lubrication of the rotation mechanism; the present invention,however, has no limitation on the material of the shaft sleeve 34. Inone embodiment, bearings 35A and 35B are respectively provided betweenthe two ends of the position-limiting barrel 33 and the wall of thereceiving space SP. The bearings 35A and 35B are provided to preventfriction between the position-limiting barrel 33 and the inner wall ofthe nail grinding pen barrel 10 when the position-limiting barrel 33 isrotated by the motor 20 along with the pushing post 32 and the gripper31. The bearings 35A and 35B also define the concentricity of theposition-limiting barrel 33. In another embodiment, the connectingelements (e.g., fixing plates and washers) connected to the bearings 35Aand 35B are made of copper or gold, or any metal coated withpolytetrafluoroethylene (PTFE), hard chrome-plated, nickel-plated, orlubricated, or they can be thrust bearings; the invention, however, hasno limitation on the material of those connecting elements.

For the design of the rotating shaft of the motor, please refer to FIG.7A-7F, which show various rotating shaft designs for the motor in thepresent invention. In the embodiments shown in FIG. 7A-7F, the rotatingshafts are respectively designed as a shaft 21A with a circular crosssection (see FIG. 7A), a shaft 21B with a cross-shaped cross section(see FIG. 7B), a shaft 21C with a D-shaped cross section (see FIG. 7C),and shafts 21D and 21E with a polygonal cross section (see FIG. 7D for aquadrilateral cross section and FIG. 7E for a pentagonal cross section).In fact, the rotating shaft of the motor may have any othercross-sectional shape without limitation. In another embodiment, anadditional sleeve 211 is attached to and mounted around the rotatingshaft 21 of the motor in the invention (see FIG. 7F), and the shaftsleeve 34 is fixed to the rotating shaft 21 via the additional sleeve211. The invention has no limitation on the shape of the additionalsleeve 211.

Please refer to FIG. 8 for a partial sectional view of the nail grindingpen in FIG. 1 to FIG. 3 . As shown in FIG. 8 , the gripper 31 includes asleeve 311 connected to the pushing post 32, an accommodating groove 312provided at one end of the sleeve 311 and facing the opening OP, and aplurality of claw units 313 provided along the periphery of theaccommodating groove 312. The accommodating groove 312 is configured toaccommodate the grinding head GH. A gap SG is formed between each twoadjacent claw units 313 so that the claw units 313 can constrictradially to grip the grinding head GH or can expand radially to releasethe grinding head GH.

In one embodiment, the gripper 31 includes three claw units 313. Inother embodiments, the number of the claw units 313 may be four, five,six, or a greater number. Changes in the number of the claw units 313shall be viewed as falling within the scope of the present invention. Toprovide an appropriate gripping force and prevent the grinding head GHfrom separating from the gripper 31, one embodiment is so designed thatwhen the claw units 313 are closed, the gap between each two adjacentclaw units 313 is smaller than 0.7 mm, such as but not limited to 0.10mm, 0.15 mm, 0.20 mm, 0.25 mm, 0.30 mm, mm, 0.40 mm, 0.45 mm, 0.50 mm,0.55 mm, 0.60 mm, or 0.65 mm; the invention has no limitation in thisregard. In one embodiment, the depth of the accommodating groove 312 isbetween 20 mm and 38 mm, such as but not limited to 20 mm, 21 mm, 22 mm,23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm, 33mm, 34 mm, 35 mm, 36 mm, 37 mm, or 38 mm; the invention has nolimitation in this regard either.

In order for the gripper 31 to be switchable between an opened state anda closed state, one embodiment is so designed that the gripper 31 isrestricted between a front position and a rear position, can be movedforward in order to be switched to the opened state, and can be movedrearward in order to be switched to the closed state. Please refer toFIG. 9 for another partial sectional view of the nail grinding pen inFIG. 1 to FIG. 3 . As shown in FIG. 9 , the rotary switch 11B includes arotating ring 111B, a position-limiting track 112B disposed on the nailgrinding pen barrel 10 and surrounded by the rotating ring 111B, aconnecting ring 113B provided on the inner side of the position-limitingtrack 112B, and a rolling ball 114B provided on the connecting ring 113Band confined in the position-limiting track 112B. The outer periphery ofthe connecting ring 113B is provided with an annular track AT forinterfering with the rolling ball 114B. By rotating the rotating ring111B, the rolling ball 114B can be moved in and along theposition-limiting track 112B between a first axial position and a secondaxial position such that the connecting ring 113B is moved in the axialdirection due to interference and limitation by the position-limitingtrack 112B and thereby pushes the gripper 31 forward or rearward. In oneembodiment, the rolling ball 114B can be locked at a first end P1 or asecond end P2 of the position-limiting track 112B, wherein the first endP1 is the end of the position-limiting track 112B that faces the firstaxial position while the second end P2 is the end of theposition-limiting track 112B that faces the second axial position. As tothe locking method, one embodiment is so designed that a spring 115B isprovided on one side of the connecting ring 113B to apply an elasticforce to the connecting ring 113B in the axial direction, therebyapplying an auxiliary force to the connecting ring 113B to secure therolling ball 114B either in the first position-limiting groove P11 atthe first end P1 of the position-limiting track 112B or in the secondposition-limiting groove P21 at the second end P2 of theposition-limiting track 112B In order for the rolling ball 114B to beable to roll along with the rotating ring 111B and move in the axialdirection, the inner side of the rotating ring 111B is provided with aconfining track LT that extends in the axial direction, and the rollingball 114B is located in the confining track LT.

The “first axial position” in the present invention is a position in thenail grinding pen 100 that is relatively close to the rear end (or arear cover 12, as defined further below) of the nail grinding pen 100 inthe axial direction (i.e., relatively close to the right side of FIG. 9), whereas the “second axial position” is a position in the nailgrinding pen 100 that is relatively close to the front end (or theopening OP) of the nail grinding pen 100 in the axial direction (i.e.,relatively close to the left side of FIG. 9 ).

Please refer to FIG. 10 for still another partial sectional view of thenail grinding pen in FIG. 1 to FIG. 3 . As shown in FIG. 10 , thegripper 31 includes a constricting unit 314. The constricting unit 314is provided inside the position-limiting barrel 33, is mounted aroundthe sleeve 311, and constricts the claw units 313 in normalcircumstances. The inner side of the position-limiting barrel 33 isprovided with an inner wall 332 facing one end of the constricting unit314, and the pushing post 32 is provided with a front wall 321 facingthe other end of the constricting unit 314. When the connecting ring113B pushes the gripper 31 via the pushing post 32, the constrictingunit 314 is compressed in two opposing directions and therefore expandsradially to reduce the constricting force of the claw units 313, therebyallowing the grinding head GH to be replaced. In one embodiment, theconstricting unit 314 is, for example but not limited to, a spring or aleaf spring; the invention has no limitation in this regard.

Please refer to FIG. 11A-11F, the foregoing structural configurationsare such that the moving path of the rolling ball 114B is essentiallylimited by interference of the position-limiting track 112B on the nailgrinding pen barrel 10, by interference of the annular track AT on theouter periphery of the connecting ring 113B, and by interference of theconfining track LT on the inner side of the rotating ring 111B.Referring to FIG. 11A, FIG. 11B, and FIG. 11C, when the rotating ring111B is rotated (e.g., clockwise), the rolling ball 114B is moved fromthe first end P1 toward the second end P2 of the position-limiting track112B by the rotating ring 111B, as indicated by the arrow A3 in FIG.11A. With the rolling ball 114B moving from the first end P1 to thesecond end P2, the connecting ring 113B, which is located on the innerside of the rolling ball 114B, is pushed by the rolling ball 114B andthus moved from the first axial position toward the second axialdirection, as indicated by the arrow A4 in FIG. 11B. The connecting ring113B, in turn, pushes and moves the pushing post 32 and the gripper 31such that the constricting unit 314 is compressed from both ends by thefront wall 321 of the pushing post 32 and the inner wall 332 on theinner side of the position-limiting barrel 33. As a result, theconstricting unit 314 is radially expanded (see FIG. 11C), and theinclined walls 3131 at the distal ends of the claw units 313 are movedaway from the bell-shaped opening of the position-limiting barrel 33 toallow removal of the grinding head GH. To mount the grinding head GH,referring to FIG. 11D, FIG. 11E, and FIG. 11F, the rotating ring 111B isrotated in the opposite direction (e.g., counterclockwise), therebymoving the rolling ball 114B from the second end P2 toward the first endP1 of the position-limiting track 112B, as indicated by the arrow A5 inFIG. 11D. With the rolling ball 114B moving from the second end P2 tothe first end P1, the connecting ring 113B, which is located on theinner side of the rolling ball 114B, is pushed by the rolling ball 114Band thus moved from the second axial position toward the first axialdirection, as indicated by the arrow A6 in FIG. 11E. Once the connectingring 113B is moved, the forces applied respectively to the two ends ofthe constricting unit 314 are removed such that the constricting unit314 constricts radially and restores its original position (see FIG.11F) as the distance between the front wall 321 of the pushing post 32and the inner wall 332 on the inner side of the position-limiting barrel33 is increased. Consequently, the inclined walls 3131 at the distalends of the claw units 313 are brought back into the bell-shaped openingof the position-limiting barrel 33 to secure the grinding head GH.

The motor 20 may be a brushless motor or a brushed motor; the presentinvention has no limitation in this regard. In one embodiment, the motor20 has a rotation speed lower than 40000 RPM. More specifically, therotation speed of the motor 20 may be, but is not limited to, 5000 RPM,6000 RPM, 7000 RPM, 8000 RPM, 9000 RPM, 10000 RPM, 11000 RPM, 12000 RPM,13000 RPM, 14000 RPM, 15000 RPM, 16000 RPM, 17000 RPM, 18000 RPM, 19000RPM, 20000 RPM, 21000 RPM, 22000 RPM, 23000 RPM, 24000 RPM, 25000 RPM,26000 RPM, 27000 RPM, 28000 RPM, 29000 RPM, 30000 RPM, 31000 RPM, 32000RPM, 33000 RPM, 34000 RPM, 35000 RPM, 36000 RPM, 37000 RPM, 38000 RPM,or 39000 RPM; the invention has no limitation in this regard. In oneembodiment, the drive voltage for driving the motor 20 to rotate at thehighest speed is higher than 4 V. More specifically, the drive voltageof the motor 20 may be, but is not limited to, 5 V, 6 V, 7 V, 8 V, 9 V,10 V, 11 V, 12 V, 13 V, 14 V, 15 V, 16 V, 17 V, 18 V, 19 V, 20 V, 21 V,22 V, 23 V, 24 V, or 25 V; the invention has no limitation in thisregard.

Please refer to FIG. 12A-12C for various electrical connection portdesigns for the motor in the present invention. In one embodiment, theelectrical connection ports of the motor 20 are in the form of aplurality of electrical sockets 23A, as shown in FIG. 12A. When theelectrical connection ports are designed as the electrical sockets 23A,the power cord to be connected to the electrical connection ports mayhave a plug corresponding to the electrical sockets 23A so thatelectrical connection can be established by connecting the plug of thepower cord to the electrical sockets 23A of the motor 20. In anotherembodiment, the electrical connection ports of the motor 20 are in theform of terminals 23B, as shown in FIG. 12B, and when the electricalconnection ports are designed as the terminals 23B, the power cord to beconnected to the electrical connection ports may have a socketcorresponding to the terminals 23B so that electrical connection can beestablished by inserting the terminals 23B of the motor 20 into thesocket of the power cord. In yet another embodiment, the electricalconnection ports of the motor 20 are in the form of soldered wires 23C,as shown in FIG. 12C, and when the electrical connection ports aredesigned as the soldered wires 23C, the power cord to be connected tothe electrical connection ports may have wires or solder padscorresponding to the soldered wires 23C so that electrical connectioncan be established by soldering the soldered wires 23C of the motor 20to the wires or solder pads of the power cord. Changes in design of theelectrical connection ports of the motor 20 shall be viewed as fallingwithin the scope of the invention.

Please refer to FIG. 13A and 13B for partial sectional views of two nailgrinding pens according to the present invention. As shown in thedrawing, the nail grinding pen barrel 10 in the invention is providedwith a rear cover 12 at the rear end, and the rear cover 12 isconfigured to close the receiving space SP from the rear side. In theembodiment shown in FIG. 13A, the rear side of the rear cover 12 isprovided with an electrical wire having a protective sleeve 121 throughwhich a power cord can pass, and which can protect the power cord fromdamage by being bent. When the electrical connection ports of the motor20 are designed as soldered wires, the inner side of the rear cover 12will be provided with a pliable wire-surrounding member 122 forenclosing the soldered wires, and once the rear cover 12 is locked tothe nail grinding pen barrel 10, the rear cover 12 and the motor 20press tightly on the pliable wire-surrounding member 122 from twoopposite sides thereof to secure and seal the pliable wire-surroundingmember 122. In one embodiment, the pliable wire-surrounding member 122is made of flexible polyvinyl chloride (PVC), rubber, or siliconerubber; the invention, however, has no limitation on the material of thepliable wire-surrounding member 122. In the embodiment shown in FIG.13B, the electrical connection ports of the motor 20 are designed as aplurality of electrical sockets or a plurality of terminals, a powercord is inserted into the rear cover 12 from the outer side thereof andthen soldered to the electrical ports inside a pliableterminal-surrounding member 122, and the electrical ports and theelectrical socket or terminals are electrically connected through thepliable terminal-surrounding member 122. Once the rear cover 12 islocked to the nail grinding pen barrel 10, the rear cover 12 and themotor 20 press tightly on the pliable terminal-surrounding member 122from two opposite sides thereof to secure and seal the pliableterminal-surrounding member 122.

In another embodiment as shown in FIG. 14 , which shows a partialsectional view of a nail grinding pen according to the presentinvention, the rear cover 12 is dispensed with. As shown in the drawing,the rear end of the nail grinding pen barrel 10 has a rear opening 15,and the rear opening 15 is provided with a position-limiting portion151. The position-limiting portion 151 is located on the outer side of apliable wire-surrounding member 16 with respect to the rear opening 15so as to prevent the pliable wire-surrounding member 16 from leaving therear opening 15 from inside the receiving space SP, wherein the pliablewire-surrounding member 16 closes the receiving space SP by closing therear opening 15. In one embodiment, the position-limiting portion 151is, for example, a protruding ring provided on the inner periphery ofthe rear opening 15 to prevent the pliable wire-surrounding member 16from separating from the rear opening 15. In another embodiment, theposition-limiting portion 151 is formed by gradually reducing thereceiving space SP toward the rear opening 15 such that the innerdiameter of the tapered end of the receiving space SP is smaller thanthe outer diameter of the pliable wire-surrounding member 16, causinginterference between the rear opening 15 and the pliablewire-surrounding member 16 and thereby preventing the pliablewire-surrounding member 16 from separating from the rear opening 15.

In one embodiment, the material of the pliable wire-surrounding memberis, for example but not limited to, flexible PVC, rubber, or siliconerubber; the present invention has no limitation in this regard.

Please refer to FIG. 15 for another partial sectional view of the nailgrinding pen in FIG. 1 to FIG. 3 . As shown in FIG. 15 , the nailgrinding pen barrel 10 is provided with a grip portion 13 to facilitateoperation of the nail grinding pen 100. The grip portion 13 has anergonomic design in terms of its thickness so that the nail grinding pen100 can be easily held by the grip portion 13. In one embodiment, thegreatest gripping comfort can be achieved by providing the nail grindingpen barrel 10 with a width less than 32 mm, such as but not limited to 8mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm,19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29mm, 30 mm, or 31 mm; the invention has no limitation in this regard. Inone embodiment, the grip portion 13 is provided with a cool-feelingmaterial, and the cool-feeling material may be, but is not limited to, agel, silicone, or polyester fiber; the invention has no limitation inthis regard. In one embodiment, the grip portion 13 is provided with acushioning material corresponding to the inner side or the outer side ofthe nail grinding pen barrel 10. When corresponding to the outer side ofthe nail grinding pen barrel 10, the cushioning material may cover thegrip portion 13 and an area extending from the grip portion 13. Whencorresponding to the inner side of the nail grinding pen barrel 10, thecushioning material may cover the contact surfaces between theposition-limiting barrel 33 and the bearings 35A and 35B, or cover thecontact surfaces between the bearings 35A and 35B and the nail grindingpen barrel 10, or lie between the position-limiting barrel 33 and thenail grinding pen barrel 10, in order to absorb the vibrations generatedby the motor 20 rotating the inner body 30. To protect the nail grindingpen barrel 10 from damage by solvents, the nail grinding pen barrel 10in one embodiment is made of an acetone-resistant material or has acoating, the nail grinding pen barrel 10 in another embodiment has asurface with a polyurethane (PU) paint layer or a UV-resistant paintlayer, the nail grinding pen barrel 10 in still another embodiment has asurface with a metal coating layer, and the nail grinding pen barrel 10in yet another embodiment has a surface with a layer formed by waterelectroplating; the invention has no limitation on such a protectivematerial or coating.

Please refer to FIG. 16 for still another partial sectional view of thenail grinding pen in FIG. 1 to FIG. 3 . In the embodiment shown in FIG.16 , the nail grinding pen barrel 10 includes a dust cover 14 attachedto the gap between the wall of the opening OP of the nail grinding penbarrel 10 and the position-limiting barrel 33 to prevent the nail dustgenerated by nail grinding from entering the interior of the nailgrinding pen barrel 10 through the opening OP (or more particularlythrough the aforesaid gap) and hence from making the electromechanicaldevices inside the nail grinding pen barrel 10 malfunction.

Please refer to FIG. 17A and 17B for two nail grinding pens according tothe present invention, each incorporating a fan. In the embodimentsshown in the drawing, the nail grinding pen 10 is further provided witha fan to dissipate heat from the electromechanical parts (e.g., themotor 20) inside the nail grinding pen barrel 10. In the embodimentshown in FIG. 17A, a fan FF1 is provided inside the nail grinding penbarrel 10 by way of example and is supplied with electricity throughinternal wires inside the nail grinding pen barrel 10 (e.g., by way ofthe pliable wire-surrounding member 16). In the embodiment shown in FIG.17B, a fan FF2 is mounted directly around the nail grinding pen barrel10 by way of example, is configured to dissipate the heat of the nailgrinding pen barrel 10 from the outside and thereby dissipate heat fromthe electromechanical parts inside the nail grinding pen barrel 10, andis driven by electricity supplied either through external wires or by anindependent power source. Changes in the mounting method and powersupply circuitry of the fan shall be viewed as falling within the scopeof the invention.

Please refer to FIG. 18 for a partial perspective view of a nailgrinding pen according to the present invention. As shown in thedrawing, a front end portion of the nail grinding pen barrel 10 isperipherally provided with heat dissipation slots 16 to enhance heatdissipation efficiency. The term “front end portion” refers to aperipheral wall portion of the nail grinding pen barrel 10 that isadjacent to the opening OP. The slots 16 allow the heat generated byoperation of, or friction between, the electromechanical parts insidethe nail grinding pen barrel 10 to be dissipated effectively. To satisfypractical nail grinding needs, the grinding head GH in one embodimenthas a diameter preferably ranging from 2.2 mm to 3.2 mm, such as but notlimited to 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9mm, 3.0 mm, 3.1 mm, or 3.2 mm; the invention has no limitation in thisregard.

Please refer to FIG. 19A and 19B, which show two nail grinding pensaccording to the present invention, each incorporating an auxiliarylight. In order to provide proper lighting during the nail grindingprocess and thereby allow the operator to better see the nail grindingeffects and details, the nail grinding pen barrel 10 in each embodimentin FIG. 19A and 19B is provided with an auxiliary light. In oneembodiment, the auxiliary light may be, for example but not limited to,a LED, an annular light, a homogeneous light, or an optical fiber; theinvention has no limitation in this regard. In the embodiment shown inFIG. 19A, an auxiliary light 17A is incorporated into the nail grindingpen barrel 10 and obtains electricity through internal wires inside thenail grinding pen barrel 10 (e.g., is electrically connected to thepliable wire-surrounding member 16 through internal wires). In theembodiment shown in FIG. 19B, an auxiliary light 17B is mounted on theouter side of the nail grinding pen barrel 10 and is driven byelectricity supplied either through external wires outside the nailgrinding pen barrel 10 or by an independent power source. Changes in themounting method and power supply circuitry of the auxiliary light shallbe viewed as falling within the scope of the invention.

The present invention further provides a nail grinding host machine 200for use with the nail grinding pen 100, as described below withreference to the embodiment illustrated in FIG. 20 , FIG. 21 , and FIG.22 , which show the exterior, the internal devices, and a block diagramof a nail grinding host machine according to the invention,respectively. The nail grinding host machine 200 according to theembodiment shown in the drawings is connected to the foregoing nailgrinding pen 100 in order to control the operating mode of the motor 20in the nail grinding pen 100.

The nail grinding host machine 200 includes a host machine body 40 and amain board 50. The host machine body 40 is provided with at least oneman-machine interface 41. The main board 50 is provided in the hostmachine body 40, is connected to the man-machine interface 41, and isconfigured to receive instructions from and send instructions to theman-machine interface 41. The main board 50 includes a power module 51,at least one driver 52, and a microcontroller C1 connected or coupled tothe man-machine interface 41 and the driver 52. The main board 50 isconnected through wires, or is coupled, to the motor 20 of the nailgrinding pen 100 in order to transmit control instructions and drivingpower to the motor 20 and thereby control the operation of the motor 20.In one embodiment, the microcontroller C1 and the driver 52 may beco-constructed as a single chip or implemented as different chips; thepresent invention has no limitation in this regard.

The main board 50 is not necessarily a single circuit board. Morespecifically, the main board 50 may be composed of a plurality ofcircuit boards to meet the requirements in function, circuit design, ormechanism layout. For example, the main board 50 may be composed of aplurality of sub-functional circuit boards due to the fact that, inpractice, the product corresponding to each function of the main board50 may be provided with an independent circuit board by itsmanufacturer. Changes in the number of such circuit boards shall beviewed as falling within the scope of the present invention.

When the motor 20 is a brushless motor, the driver 52 in this embodimentmay be, for example but not limited to, a three-phase inverter, a buckconverter, a boost converter, a pulse-amplitude modulator (PAM), apulse-width modulator (PWM), a pulse-position modulator (PPM), avariable-frequency drive (VFD), or other similar devices that can drivea brushless motor with a square wave, a six-step square wave, or a sinewave, or by field-oriented control (FOC). When the motor 20 is a brushedmotor instead, the driver 52 may, apart from being any of the aforesaiddrivers, include a converter, switch, metal-oxide-semiconductor (MOS)device, voltage stabilizer, or relay that can provide a voltage to andthereby drive a brushed motor. In one embodiment, the MOS device 522 ofthe brushless or brushed motor driver 52 may be externally connected toa chip including the driver 52 or be a built-in element of the chip; thepresent invention has no limitation in this regard. In an embodimentwhere the motor 20 is a brushed motor, forward and reverse rotation ofthe motor 20 is switched by a switching device; the invention, however,has no limitation in this regard. In one embodiment, the switchingdevice may be, but is not limited to, an H-bridge, a MOS device, or arelay; the invention has no limitation in this regard either.

In one embodiment, the man-machine interface 41 may be, for example butnot limited to, a rotating knob, a pushbutton, a liquid crystal displayscreen, a touchpad, a touch-controlled button, a touch screen, LED, LEDdisplay, slide switch, rocker switch, or a combination of the above; thepresent invention has no limitation in this regard. In one embodiment,the man-machine interface 41 includes a motor speed regulator 411, andthe motor speed regulator 411 includes a varistor or an encoder. Themotor speed regulator 411 comprises a varistor or an encoder, which isused by the driver 52 to control the rotation speed of the motor 20accordingly, wherein the driver 52 is driven by either the voltage levelor a PWM signal.

Please refer to FIG. 23A to FIG. 23E for block diagrams of somealternative nail grinding host machines according to the presentinvention. In the embodiment shown in FIG. 23A, the main board 50includes a rotation speed detector 53 connected or coupled to the driver52 and the motor 20. The rotation speed detector 53 is configured todetect the rotation speed of the motor 20 and provide feedback to thedriver 52 in order to modify the output of the driver 52. In anotherembodiment, the rotation speed detector 53 detects the rotation speed ofthe motor 20 by detecting the induced voltage generated by rotation ofthe motor 20, with the term “induced voltage” referring to the voltagegenerated in a rotating magnetic field. In the embodiment shown in FIG.23B, the motor 20 includes a built-in Hall sensor H1, and the rotationspeed detector 53 detects the rotation speed of the motor 20 via thebuilt-in Hall sensor H1 of the motor 20. In the embodiment shown in FIG.23C, the rotation speed detector 53 detects the rotation speed of themotor 20 via a Hall sensor H2 that is externally connected to the motor20, and such a change in the connection method of the Hall sensor shallbe viewed as falling within the scope of the invention. In theembodiment shown in FIG. 23D, and by way of example only, the rotationspeed detector 53 detects the rotation speed of the motor 20 via adirect-current tachometer H3 that is externally connected to the motor20. In the embodiment shown in FIG. 23E, and by way of example only, therotation speed detector 53 detects the rotation speed of the motor 20via a rotary transformer H4 that is externally connected to the motor

When contacting the surface of a nail, the grinding head GH of the nailgrinding pen 100 may be subjected to different levels of resistance suchthat the rotation speed of the motor 20 (equivalent to the force appliedto the nail by the nail grinding pen 100) is changed and becomesinconsistent. In order to maintain the rotation speed of the grindinghead GH (or the motor 20), the microcontroller C1 detects the rotationspeed of the motor 20 via the rotation speed detector 53 and, when therotation speed of the motor 20 is reduced, increases the output of themotor 20 to compensate for the reduced rotation speed. Morespecifically, the microcontroller C1 may set a rotation speed thresholdaccording to the current rotation speed and, when the rotation speedthreshold has yet to reached, increase the rotation speed of the motor20 either at once or gradually until the rotation speed threshold isreached. In another embodiment, the rotation speed threshold includes alower limit Threshold 1 and an upper limit Threshold 2 higher than thelower limit Threshold 1. When the rotation speed value fed back to themicrocontroller C1 is lower than the lower limit Threshold 1, themicrocontroller C1 increases the rotation speed of the motor 20 until itis higher than the lower limit Threshold 1. When the rotation speedvalue fed back to the microcontroller C1 is higher than the upper limitThreshold 2, the microcontroller C1 reduces the rotation speed of themotor 20 until it is lower than the upper limit Threshold 2. Theforegoing design helps prevent the motor 20 from rotating too fast whenthe grinding head GH leaves the surface of a nail. In an embodimentwhere the microcontroller C1 is dispensed with, the driver 52 detectsthe rotation speed of the motor 20 via the rotation speed detector 53and, when the rotation speed of the motor 20 is reduced, increases theoutput of the motor 20 to compensate for the reduced rotation speed. Inanother embodiment, the microcontroller C1 or the driver 52 may increasethe switching speed of a MOS device, adjust a duty ratio or voltage, orperform self-adaptive I×R compensation in order to control the output ofthe driver 52 and thereby carry out rotation speed compensation.

Please refer to FIG. 24A-24C for block diagrams of some more alternativenail grinding host machines according to the present invention. In theembodiment shown in FIG. 24A, the driver 52 includes a comparator 521for detecting whether or not a feedback voltage V1 (or current) hasreached a setting value TH. If the setting value is reached, the outputpower to the motor 20 will be maintained; otherwise, compensation forthe output will continue until the feedback voltage or current reachesthe setting value. In the embodiment shown in FIG. 24B, themicrocontroller C1 carries out self-adaptive regulation by receiving afeedback parameter V2 of the motor 20, calculating the correspondingcompensation value from the feedback parameter, and controlling theoutput of a MOS device or the driver 52 according to the compensationvalue. In the embodiment shown in FIG. 24C, the microcontroller C1performs self-adaptive regulation by receiving a feedback parameter ofthe motor 20, finding the corresponding compensation value in a lookuptable, and controlling the output of a MOS device or a voltagestabilizer according to the compensation value.

Please refer to FIG. 25A-25E for the receiving mechanisms of differentnail grinding host machines according to the present invention. In oneembodiment, the host machine body 40 is provided with a receivingmechanism for receiving the grinding head GH. In the embodiments shownin FIG. 25A-25C, the receiving mechanisms include a receiving box 42Afor receiving the grinding head GH (see FIG. 25A); a plurality ofreceiving blocks 42B so that the grinding head GH can be engaged in anyof the gaps 421B between the receiving blocks 42B (see FIG. 25B); and areceiving groove 42C sunken into the host machine body 40 so that thegrinding head GH can be engaged and received in the engaging groove 42C(see FIG. 25C). In another embodiment, the receiving mechanism 42 isprovided with one or a plurality of magnetic units 421 for magneticallyattracting and thereby retaining the grinding head GH (see FIG. 25D). Inyet another embodiment, the receiving mechanism 42 is provided with oneor a plurality of engaging units 422 so that the grinding head GH can beengaged and secured in the one or plurality of engaging units 422 (seeFIG. 25E).

In one embodiment, the nail grinding host machine 200 includes areplaceable or rechargeable battery connected to the power module 51. Inembodiments that use a rechargeable battery, the power module 51 mayinclude, for example, a recharging module, and the recharging module mayor may not support a rapid-charging function for increasing theefficiency with which a rechargeable battery can be recharged. In oneembodiment, the charging current ranges from 0.3 c to 1 c, the unit “c”refers to the charging rate in relation to the battery capacity. In oneembodiment, the power module 51 includes an electrical socket located onthe host machine body 40, and the electrical socket may be exposed fromthe host machine body 40 or include a dust cover or dust shield that cancover the electrical socket to ward off dust and water or repel water.In one embodiment, this electrical socket may be, for example but notlimited to, a USB Type-C socket. Changes in configuration of theelectrical socket shall be viewed as falling within the scope of thepresent invention.

Please refer to FIG. 26 for a block diagram of another nail grindinghost machine according to the present invention. As shown in thedrawing, the main board 50 includes an over-current protection moduleM1, an over-voltage protection module M2, and an over-temperatureprotection module M3, each connected to the microcontroller C1. Theover-current protection module M1 may include, for example but notlimited to, a current detector. The over-current protection module M1produces decision information upon detecting that the input current onthe secondary side (corresponding to the input into the motor 20)exceeds a safe value. The over-voltage protection module M2 may include,for example but not limited to, a voltage detector. The over-voltageprotection module M2 produces decision information upon detecting thatthe voltage exceeds a safe value. In one embodiment, the over-voltageprotection module M2 is provided on the driver 52 and is configured totrack the input of the motor 20. In other embodiments, the over-voltageprotection module M2 may be provided anywhere in the circuit on thesecondary side of the power module 51 in order to detect the voltageacross an arbitrary node. The invention has no limitation on thelocation of the over-voltage protection module. The over-temperatureprotection module M3 may include, for example but not limited to, atemperature sensor or a thermistor. The over-temperature protectionmodule M3 produces decision information upon detecting that thetemperature of the motor 20 exceeds a safe value. In one embodiment, thedecision information may be, but is not limited to, a power-offinstruction, circuit-breaking instruction, or warning instruction to themicrocontroller C1; the invention has no limitation in this regard. Inanother embodiment, the decision information may be sent directly to thepower module 51. The invention has no limitation on whether the decisioninformation is sent to the power module 51 directly or otherwise.

In order to provide enhanced operability and safety, the nail grindinghost machine of the present invention can be paused according to a pauseinstruction triggered by a user instruction or by a predeterminedoperation state. In one embodiment, the microcontroller C1 stops themotor 20 upon detecting that the pause instruction is triggered via theman-machine interface 41. In another embodiment, the microcontroller C1stops the motor 20 when the pause instruction is triggered by the degreeof inclination of the nail grinding pen 100 as is detected by theinclinometer of the nail grinding pen 100. More specifically, theinclinometer of the nail grinding pen 100 is connected or coupled to themain board 50 or the microcontroller C1. When the inclinometer detectsthat the nail grinding pen 100 is placed horizontally, themicrocontroller C1 determines that the user has stopped operating thenail grinding pen 100, and in consequence, the microcontroller C1triggers the pause instruction to pause the motor 20. As the angle valuedetected by the inclinometer will vary with the inclination angle atwhich the inclinometer is mounted in/on the nail grinding pen 100, theinvention has no limitation on the angle detected by the inclinometer.Please refer to FIG. 27 , which shows an angle between a nail grindingpen according to the invention and a horizontal plane, or moreparticularly the angle θ1 between the pen body of the nail grinding pen100 and a horizontal plane in the world coordinate system. The angle θ1that will trigger the pause instruction preferably ranges from −10° to10° and may be, but is not limited to, −10°, −9°, −8°, −7°, −6°, −5°,−4°, −3°, −2°, −1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, or 10°, theinvention has no limitation in this regard. In one embodiment, themicrocontroller C1 stops the motor 20 when the pause instruction istriggered by the motion sensor of the nail grinding pen 100 detectingthat the nail grinding pen 100 has been still for a predetermined amountof time. In another embodiment, the main board 50 or the microcontrollerC1 includes a timer that will trigger a shut-down instruction when thenail grinding pen 100 has been still for a predetermined amount of time.The time-related pause in the last two embodiments can preventunnecessary power consumption and eliminate safety concerns while thenail grinding pen 100 is not in operation. In one embodiment, themicrocontroller C1 controls the power of the motor 20 at a stablewattage lower than 13 W when the motor 20 is idling; thus, by limitingthe driving power of the motor 20, safety issues associated with damageand/or too high a rotation speed of the motor 20 are prevented. Thestable wattage may be set at, for example, 5 W, 6 W, 7 W, 8 W, 9 W, 10W, 11 W, or 12 W; the invention has no limitation in this regard.

The present invention may dispense with the microcontroller and use onlythe driver to drive the motor. Please refer to FIG. 28 for a blockdiagram of yet another nail grinding host machine according to theinvention. In the embodiment shown in the drawing, the nail grindinghost machine 300 essentially includes a host machine body 40 and a mainboard 50. The host machine body 40 is provided with at least oneman-machine interface 41. The main board 50 is provided in the hostmachine body 40, is connected to the man-machine interface 41, and isconfigured to receive instructions from and send instructions to theman-machine interface 41. The main board 50 includes a power module 51.The main board 50 is connected through wires, or is coupled, to themotor 20 of the nail grinding pen 100 in order to transmit controlinstructions and driving power to the motor 20. The motor 20 is abrushed motor, and the man-machine interface 41 is connected to thedriver 54 of the brushed motor. The driver 54 serves to provide avoltage output for the brushed motor.

In contrast to its brushless counterpart in the previous embodiments,the motor in this embodiment is a brushed motor and can be implementedwithout using the microcontroller C1. All that is needed to control theactivation, deactivation, and rotation speed of the brushed motor is forthe driver 54 to provide, or stop providing, stable direct-current powerto the brushed motor. This embodiment is different from the previousones only in the type of the motor and the lack of the microcontrollerC1. The remaining parts of this embodiment are identical to theirrespective counterparts in the previous embodiments and therefore willnot be described repeatedly.

In one embodiment, the driver 54 may include, for example but notlimited to, a converter, a switch, a MOS device, a relay, or otherdevices that can provide electric power. In another embodiment, thedriver 54 may include, for example but not limited to, a buck converteror a boost converter.

What is claimed is:
 1. A nail grinding pen (100), comprising: a nailgrinding pen barrel (10), wherein the nail grinding pen barrel (10) hasa receiving space (SP) therein, and the nail grinding pen barrel (10)has an end with an opening (OP) in communication with the receivingspace (SP); a motor (20) provided in the receiving space (SP) and havinga rotating shall (21) to be driven to rotate by electricity; and aninner body (30) connected to the rotating shaft (21), wherein the innerbody (30) has an end facing the opening (OP) and provided with a gripper(31), and the gripper (31) is configured to secure a grinding head (GM)so that the motor (20) is able to drive the grinding head (GH) intorotation by rotating the gripper (31).
 2. The nail grinding pen (100) ofclaim 1, wherein the nail grinding pen barrel (10) is provided with arotary switch (11B) coupled to the gripper (31), and the rotary switch(11B) is configured to be rotated in order to switch the gripper (31)between an opened state and a closed state, the gripper (31) isrestricted between a front position and a rear position and is movableforward and rearward in order to he switched between the opened stateand the closed state.
 3. The nail grinding pen (100) of claim 1, whereinthe nail grinding pen barrel (10) is provided with a rotary switch (11B)coupled to the gripper (31), and the rotary switch (11B) is configuredto be rotated in order to switch the gripper (31) between an openedstate and a closed state, and the inner body (30) comprises: a pushingpost (32); the gripper (31), which is provided at a front end of thepushing post (32); a position-limiting barrel (33) surrounding thegripper (31); and a shaft sleeve (34) provided at a rear end of thepushing post (32) and attached to the rotating shaft (21) so that themotor (20) is able to drive the pushing post (32) and the gripper (31)into rotation,
 4. The nail grinding pen (100) of claim 3, wherein thegripper (31) comprises: a sleeve (311) connected to the pushing post(32); an accommodating groove (312) provided at an end of the sleeve(311), facing the opening (OP), and configured to accommodate thegrinding head (GH); and a plurality of claw units (313) provided along aperiphery of the accommodating groove (312); wherein there is a gap (SG)between each two adjacent said claw units (313) so that the claw units(313) are able to constrict radially to grip the grinding head (GH) orare able to expand radially to release the grinding head (GH), and thegripper (31) comprises three said claw units (313).
 5. The nail grindingpen (100) of claim 4, wherein there is a gap smaller than 0.7 mm betweeneach two adjacent said claw units (313) when the claw units (313) areclosed, and the accommodating groove (312) has a depth ranging from 20mm to 38 mm.
 6. The nail grinding pen (100) of claim 4, wherein therotary switch (11B) comprises: a rotating ring (111B); aposition-limiting track (112B) disposed on the nail grinding pen barrel(10) and surrounded by the rotating ring (111B), a connecting ring(113B) provided on an inner side of the position-limiting track (112B);and a rolling ball (114B) provided on the connecting ring (113B) andconfined in the position-limiting track (112B), wherein the connectingring (113B) has an outer periphery provided with an annular track (Ar)for interfering with the rolling ball (114B), and by rotating therotating ring (111B), the rolling ball (114B) is movable in and alongthe position-limiting track (112B) between a first axial position and asecond axial position such that the connecting ring (113B) is moved inan axial direction due to interference and limitation by theposition-limiting track (1128) and thereby pushes the gripper (31)forward or rearward, the rolling ball (114B) is able to be locked at afirst end (P1) or a second end (P2) of the position-limiting track(112B), and a. spring (115B) is provided on a side of the connectingring (113B) to apply an elastic force to the connecting ring (113B) inthe axial direction, thereby applying an auxiliary force to theconnecting ring (113B) to secure the rolling ball (114B) in a firstposition-limiting groove (P11) at the first end (P1) of theposition-limiting track (112B), the rotating ring (111B) has an innerside provided with a confining track (LT), and the confining track (LT)extends in the axial direction.
 7. The nail grinding pen (100) of claim6, wherein the gripper (31) comprises a constricting unit (314), and theconstricting unit (314) is provided inside the position-limiting barrel(33), is mounted around the sleeve (311), and constricts the claw units(313) in normal circumstances; and wherein the position-limiting barrel(33) has an inner side provided with an inner wall (332) facing an endof the constricting unit (314), and the pushing post (32) is providedwith a front wall (321) facing an opposite end of the constricting unit(314) so that when the connecting ring (113B) pushes the gripper (31)via the pushing post (32), the constricting unit (314) is compressed intwo opposing directions and therefore expands radially to reduce aconstricting force of the claw units (313), thereby allowing replacementof the grinding head (GH).
 8. The nail grinding pen (100) of claim 3,wherein a bearing (35A) is provided between an end of theposition-limiting barrel (33) and a wall of the receiving space (SP),and another bearing (35B) is provided between an opposite end of theposition-limiting barrel (33) and the wall of the receiving space (SP).9. The nail grinding pen (100) of claim 1, wherein the rotating shaft(21) has a circular, cross-shaped, D-shaped, or polygonal cross section,or an additional sleeve (211) is attached to the rotating shaft (21),and/or the rotating shaft (21) protrudes from the motor housing (22) bya length less than 15 mm, the motor (20) is a brushless motor or abrushed motor, and/or the motor (20) has electrical connection portsconfigured as a plurality of electrical sockets, a plurality ofterminals, or a plurality of soldered wires.
 10. The nail grinding pen(100) of claim 9, wherein a rear side of the nail grinding pen barrel(10) is provided with an electrical wire having a protective sleeve(121) which is configured to prevent a power cord passing through theprotective sleeve (121) from damage by being bent.
 11. The nail grindingpen (100) of claim 9, wherein the motor (20) has electrical connectionports configured as a plurality of soldered wires, the rear cover (12)has an inner side provided with a pliable wire-surrounding member (122)for enclosing the soldered wires, and once the rear cover (12) is lockedto the nail grinding pen barrel (10), the rear cover (12) and the motor(20) press tightly on the pliable wire-surrounding member (122) from twoopposite sides thereof to secure and seal the pliable wire-surroundingmember (122); or wherein the electrical connection ports of the motor(20) are configured as a plurality of electrical sockets or a pluralityof terminals, a power cord is inserted into the rear cover (12) from anouter side thereof and then soldered to electrical ports inside apliable terminal-surrounding member (122), the electrical ports and theelectrical sockets or the terminals are electrically connected throughthe pliable terminal-surrounding member (122), and once the rear cover(12) is locked to the nail grinding pen barrel (10), the rear cover (12)and the motor (20) press on the pliable terminal-surrounding member(122) from two opposite sides thereof to secure and seal the pliableterminal-surrounding member (122); or the nail grinding pen barrel (10)has a rear end with a rear opening (15), the rear opening (15) isprovided with a position-limiting portion (151), and theposition-limiting portion (151) is located on an outer side of a pliablewire-surrounding member (16) with respect to the rear opening (15) so asto prevent the pliable wire-surrounding member (16) from leaving therear opening (15) from inside the receiving space (SP), wherein thepliable wire-surrounding member (16) closes the receiving space (SP) byclosing the rear opening (15).
 12. The nail grinding pen (100) of claim1, wherein the nail grinding pen barrel (10) is provided with a gripportion (13), and the grip portion (13) is provided with a cool-feelingmaterial, and/or the nail grinding pen barrel (10) is provided with agrip portion (13), and the grip portion (13) is provided with acushioning material corresponding to an inner side or an outer side ofthe nail grinding pen barrel (10).
 13. The nail grinding pen (100) ofclaim 1, wherein the nail grinding pen barrel (10) is made of anacetone-resistant material or has a coating, or has a surface comprisinga polyurethane (PU) paint layer, a UV-resistant paint layer, a metalcoating layer, or a layer formed by water electroplating,
 14. The nailgrinding pen (100) of claim 1, wherein the nail grinding pen barrel (10)is provided with an auxiliary light (17), and the auxiliary light (17)is a LED, an annular light, a homogeneous light, or an optical fiber.15. A nail grinding host machine (200), connected to the nail grindingpen (100) in claim 1 to control operating mode of the motor (20) in thenail grinding pen (100), the nail grinding host machine (200)comprising: a host machine body (40), wherein the host machine body (40)is provided with at least one man-machine interface (41); and a mainboard (50) provided in the host machine body (40) and connected to theman-machine interface (41) in order to receive instructions from andsend instructions to the man-machine interface (41), wherein the mainboard (50) comprises a power module (51) and at least one driver (52),and the main board (50) is connected through wires, or is coupled, tothe motor (20) of the nail grinding pen (100) in order to transmitcontrol instructions and driving power to the motor (20).
 16. The nailgrinding host machine (200) of claim 15, wherein the man-machineinterface (41) comprises a rotating knob, a pushbutton, a liquid crystaldisplay screen, a touchpad, a touch-controlled button, a touch screen,LED, LED display, slide switch, rocker switch, or a combination of theabove, and/or the man-machine interface (41) comprises a motor speedregulator (411), the motor speed regulator (411) comprises a varistor oran encoder, which is used by the driver (52) to control the rotationspeed of the motor (20) accordingly.
 17. The nail grinding host machine(200) of claim 15, wherein the host machine body (40) is provided with areceiving mechanism (42) for receiving the grinding head (GH), whereinthe receiving mechanism (42) comprises a receiving box (42A), aplurality of receiving blocks (42B), or a receiving groove (42C), and/orthe receiving mechanism (42) is provided with one or a plurality ofmagnetic units (421) for magnetically attracting and thereby retainingthe grinding head (GH), and/or the receiving mechanism (42) is providedwith one or a plurality of engaging units (422) for securing thegrinding head (GH).
 18. The nail grinding host machine (200) of claim15, wherein the main board (50) comprises a replaceable batteryconnected to the power module (51); or the main board (50) comprises arechargeable battery connected to the power module (51); or the powermodule (51) supports a rapid-charging function, wherein the chargingspeed ranges from 0.3 c to 1 c.
 19. The nail grinding host machine (200)of claim 18, wherein the power module (51) comprises a USB Type-C socketlocated on the host machine body (40).
 20. The nail grinding hostmachine (200) of claim 15, wherein the main board (50) comprises arotation speed detector (53) for detecting a rotation speed of the motor(20) and providing feedback to the driver (52) in order to modify anoutput of the driver (52).
 21. The nail grinding host machine (200) ofclaim 20, wherein the main board (50) detects the rotation speed of themotor (20) via the rotation speed detector (53) and, upon detecting thatthe rotation speed of the motor (20) is reduced, increases an output ofthe motor (20) to compensate for the reduced rotation speed.
 22. Thenail grinding host machine (200) of claim 15, wherein the main board(50) stops the motor (20) upon detecting that a pause instruction istriggered via the man-machine interface (41).
 23. The nail grinding hostmachine (200) of claim 15, wherein the main board (50) stops the motor(20) when a pause instruction is triggered by a degree of inclination ofthe nail grinding pen (100) as is detected by an inclinometer of thenail grinding pen (100), and/or the main board (50) stops the motor (20)when a pause instruction is triggered by a motion sensor of the nailgrinding pen (100) detecting that the nail grinding pen (100) has beenstill for a predetermined amount of time, and/or the main board (50) orthe main board (50) comprises a timer for triggering a shut-downinstruction when the nail grinding pen (100) has been still for apredetermined amount of time.
 24. The nail grinding host machine (200)of claim 15, wherein the main board (50) controls power of the motor(20) at a stable wattage lower than 13 W when the motor (20) is idling.25. A nail grinding host machine (300), connected to the nail grindingpen (100) in claim 1 to control operating mode of the motor (20) in thenail grinding pen (100), the nail grinding host machine (300)comprising: a host machine body (40), wherein the host machine body (40)is provided with at least one man-machine interface (41); and a mainhoard (50) provided in the host machine body (40) and connected to theman-machine interface (41) in order to receive instructions from andsend instructions to the man-machine interface (41), wherein the mainhoard (50) comprises a power module (51), the main board (50) isconnected through wires, or is coupled, to the motor (20) of the nailgrinding pen (100) in order to transmit control instructions and drivingpower to the motor (20); wherein the motor (20) is a brushed motor, theman-machine interface (41) is connected to a driver (54) connected tothe brushed motor ; and the driver (54) provides a voltage output forthe brushed motor; wherein the driver (54) comprises a converter, aswitch, a metal-oxide-semiconductor (MOS) device, or a relay.